On 7/5/12 7:02 PM, Carsten Emde wrote:

Hi Dong,

quoted

I tried to disable CONFIG_RT_GROUP_SCHED, but I still got cpu stalls!

Just had another look at your dmesg files. Didn't you get
BUG: soft lockup - CPU#0 stuck for 279s! [swapper/0:0]
before? Now - with CONFIG_RT_GROUP_SCHED disabled - you get:
rcu_preempt detected stalls on CPUs/tasks: { 3} [..]

Is it reproducible? Maybe, there are two different problems. One leads
to soft lockups and is related to CONFIG_RT_GROUP_SCHED, and another one
that leads to rcu_preempt stalls.

The "BUG: soft lockup" error  was because I disabled RCU cpu stall 
checking by set

/sys/module/rcutree/parameters/rcu_cpu_stall_suppress

to "1"

I did try this setting after disabled CONFIG_RT_GROUP_SCHED, it didn't 
not print out any kernel error message, but the system did froze when I 
tried to start some KVM guests.

Thanks,

Dong